WRT_DENSITY

WRT_DENSITY = string
Default: WRT_DENSITY = None Description: Select which densities associated to the local potential are written as a post-processing step.

WRT_DENSITY can select one or multiple densities on the real-space grid in the unit cell to be written, e.g.,

 WRT_POTENTIAL = gradient

or

 WRT_POTENTIAL = density gradient laplacian

It writes the augmented total (core + valence) pseudo densities (charge and magnetization, their gradient, and their laplacian) that enter the XC functional on the plane-wave grid to vaspout.h5 in VASP units. That is [math]\displaystyle{ \AA^{-3} }[/math] for charge and [math]\displaystyle{ \mu_B }[/math] for the magnetization. Correspondingly, [math]\displaystyle{ \AA^{-4} }[/math] for the gradient, etc.

With LWRT_AUGMENTED_DENSITY = F the densities can be written without augmentation (compensation charge=0). Mind that the augmented densities are still used during electronic minimization to evaluate the XC functional (unlike for the MGGA specific tag LNOAUGXC).

The output is written to vaspout.h5 and can be accessed by HDF5 command-line tools (h5ls, h5dump).

 h5ls -r vaspout.h5

The above shows the table of contents of vaspout.h5. Depending on the keywords specified with WRT_DENSITY and the system it yields

 /results/gradient        Group
 /results/gradient/grid   Dataset {3}
 /results/gradient/structure Group
 /results/gradient/structure/position Group
 /results/gradient/structure/position/direct_coordinates Dataset {SCALAR}
 /results/gradient/structure/position/ion_sha256 Dataset {1}
 /results/gradient/structure/position/ion_types Dataset {1}
 /results/gradient/structure/position/lattice_vectors Dataset {3, 3}
 /results/gradient/structure/position/number_ion_types Dataset {1}
 /results/gradient/structure/position/position_ions Dataset {1, 3}
 /results/gradient/structure/position/scale Dataset {SCALAR}
 /results/gradient/structure/position/system Dataset {SCALAR}
 /results/gradient/values Dataset {12, 20, 20, 20}

The grid density can be increased by choosing a higher value for ENCUT or explicitly by NGXF, NGYF, NGZF.

The first dimension of the datasets in /results/charge_density is 1 for nonmagnetic calculation, 2 for spin-polarized calculation, and 4 for noncollinear calculations. For the datasets in /results/gradient the first dimension is multiplied by three to account for the three Cartesian directions. The components for the magnetic calculations correspond to the spinor representation with the scalar part in the first component and the magnetic part in the second (ISPIN=2) or [math]\displaystyle{ m_1 }[/math], [math]\displaystyle{ m_2 }[/math] and [math]\displaystyle{ m_3 }[/math] in the 2nd, 3rd and 4th component (LNONCOLLINEAR=T) in the basis of Pauli matrices [math]\displaystyle{ \{\sigma_1 }[/math], [math]\displaystyle{ \sigma_2 }[/math], [math]\displaystyle{ \mathbf{\sigma}_3\} }[/math] given by SAXIS.

Mind: Available as of VASP 6.6.0

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